Fluorescent agents



United States Patent Ofiice 2,723,288 Patented Nov. 8, 1955 This invention relates to novel hydroxy alkyl derivatives of 4,4-diaminostilbene sulfonic and carboxylic acids and acylated derivatives thereof which contain a free ammo group.

It is well known that cellulosic materials such as'paper, v

cotton textiles and the like have a rather slight yellowish hue which, particularly in the case of textile materials, is apt to become more pronounced when the material is subjected to repeated launderings and use. Accordingly, it has long been the practice to treat many white cotton textiles, when they are washed,.with a bluing substance, such as ultramarine. It has been found that the slight blue coloration thus imparted to the material compensates for the yellowish tint or similar oifwhite shade of the material so that it appears whiter; such bluing operations, however, result in the absorption of a measurable portion of the total visible light falling upon the treated material and, accordingly, the treated material has a slightly dull appearance. It has recently been proposed to treat paper or cotton textiles and similar cellulosic materials with agents which, while themselves colorless, fiuoresce in the blue range of the spectrum so that in daylight or other light, which includes ultra violet radiation, the fluorescence of the treating agent compensates for the slight yellowish tint or similar ofi-white shade, the blue being complementary to yellow. Such fluorescent agents only absorb a negligible portion of the visible light falling on the material and, accordingly, as a result of the fluorescence the treated material is much brighter as well as whiter in appearance. a

While a wide variety of fluorescent agents have been suggested for treatment of fibrousmaterials, it has been found that for the treatment of cellulosic materials, either paper or textiles, the use of fluorescent agents which are, I

substantive to cellulose is preferable since by the use of substantive fluorescent agents a whitening or brightening eifect which is resistant to laundering is obtained. Such substantive fluorescent agents have been applied to the material to be treated therewith either in a separate treating operation, or advantageously a small amount of the fluorescent agent may be incorporated in the soap or other detergent used for washing the textiles, and when the textile is washed with a detergent containing a fluoresalso. have a proper degree of substantivity towards the materials as toosmall a degree of substantivity renders it valueless as it would be removed in any rinse waters, and too high a degree of substantivity results in a gradual buildup of fluorescent agent on material during repeated launderings resulting in off-color shades. The fluorescent agent must be stable to light and not discolor on exposure. It must also be stable to hypo-chlorite treatment-and not discolor under such treatment, and, in addition, it must fluoresce over a fairly wide pH differential, including both alkali and acid.

I have discovered that the hydroxy alkyl derivatives of diaminostilbene sulfonic and carboxylic acids and their acylated derivatives, which may be obtained by treating diaminostilbene sulfonic or carboxylic acids or their acylated derivatives which still contain a free amino group, with an alkylene oxide, usually ethylene oxide, although propylene or butylene oxide may be employed if. desired, are decidedly superior in all the properties mentioned above to known fluorescing agents of this type which have not been so treated.

The novel hydroxy alkyl derivatives of diaminostilbene sulfonic acid and its acylated derivatives which still contain a free amino group may be represented by the following general formula:

R-OH

'2,2,6,6'-stilbenetetrasulfonic acid, 4,4-diamino-2,2-stilbenedicarboxylic acid or 4,4-diamino3,3-stilbenedicarboxylic acid. All of these acids yield products having substantially similar properties. The 4,4-diamino-2,2-

stilbnedisulfonic acid is generally used and therefore the present invention will be described with particular referof novel compounds of this invention and their process cent brightening agent, a small amount is picked up by the material so that after drying the material appears much whiter and brighter than untreated materials. These fluorescent brightening agents arealso useful in treating textile materials which are to be, or have been dyed or printed with discharge paste. The whites of the materials so printed with pastes containing brightening agents are much whiter than is otherwise the case. While numerous fluorescent leaching or brightening agents have heretofore been suggested, including diaminostilbene sulfonic and carboxylic acids and certain of preparation. In these examples the parts are by weight. Example I i... NHGO N L CHn-OHzOH OJNB I The pure compound may be obtained by a recrystallization from water. I

3 4 Example II amine salts of the free acids such as the cyclohexylamine Forty parts by weight f Sodium 4 [p (Pamihobehzasalts may be produced by methods .known in the art. The mido)behzamido] 4' 2 2' 1 alkaline earth metal salts such as the barium and calc1um disulfonate, 300 parts by Weight of water, 2 parts by Sens: which e Obtained e the free e y weight f 20 B hydrochloric acid and 45 vparts by 5 double decomposition of the sodium or potassium salts, weight of ethylene oxide were heated in an autoclave for are of interest for the brightening of Photographle P 5 hours at 75 C ft which the mass was allowed The thus-obtained fluorescent agents are valuable addrto cool to 25 C. by stirring 8-10 hours. Five hundred fives to Seal) and other detergents. as b11ghten 1ng agents parts b i h f Wathr d 100 parts b Weight f l for cellulosic materials to be washed therew1th. They were added and the mass stirred at 2 25 C. f may also be applied to cellulosic materials, either textiles hours until crystallization was completed. The product of P p y means of a Separate treating Process in Order was filtered from the mother liquor and dried at 100 C. to substantially brighten the treated material.

in vacuum. Yield: 65 parts by weight of product which I claim:

is principally a compound having the formula: 1. Fluorescent agents selected from the group consist- AOsNa Thev pure compound may be obtained by a recrystallizaing of compounds of the formula tion from water. SOaH Example III I I /R-OH One hundred and eighty-five parts by weight of 4,4'- CH diarnino-2,'2'-stilbenedisulfonic acid was slurried with 600 L parts by weight of water. The pI-I'Was adjusted to approximately 6.5 by the addition of caustic soda solution I and the mixture treated in an autoclave with 105 parts by O-" weight of ethylene oxide. The temperature was raised A L I 0 to 75 C. and maintained at 7S80 C. for four hours. 03H The mixture Was cooled to 20-25 C. while stirring overwh r n n r pr n s, n in g r of from 0 to 4, inclunight and then filtered. The dried paste amounted to sive', th R in each Case" represents an alkylene p- 197 parts by weight of product which is principally a ing having 2 t'o 4 carbon atoms and salts of such comcompound having the formula: pounds.

I 2. Fluorescent agents which in the form of their free 40 acids have the formula gOaNa '2 I /CH2CH2OH The pure compound may be obtained by a recrystallization from water. l- 1 CHr-CHZOH The foregoing examples are illustrative of preferred SOaH 1 fluorescent agents embodied in the present invention and 3. Fluorescent agents which in the form of their free their method of manufacture. It will be understood, acids have the formula I TED-NEG OO-NHO oQaswm-cmonn LIL-O-NHO o N (cur-0 HzOH) z however, that these materials may be modified as previ 4. Fluorescent agents which in the form of their free ously indicated. Thus, in place of the 4,4'-diamino-'2,2- acids have the formula stilbenedisulfonic acid which was employed in these examples, other diaminostilbene sulfonic or car'boxylic 7 :GH N(CH1CH2OH)2 acids of the type previously indicated may be used. It L Will also be understood that in place of ethylene oxide SOsH which was employed in the specific examples, other alv kylene oxides, i. e., propylene oxide or one of the isom- References Cted the file Ofthls Patent eric butylen'e oxides may be employed if desired. UNITED STATES PATENTS It will be apparent that in the foregoing examples the 2,139,471 Schmidt Dec 6 1938 novel products of the present invention Were obtained in Ellis et 1940 the form of their sodium salts. However, the potassium 1,256,306 Kern Sept 1941 salts have substantially similar properties and it will be 2,521,665 Hausermann Sep't 1950 apparent that they can be obtained by using the potas- 2,528,324 Thomas Oct 1950 sium salt of the acylated (or unacylated) diaminostilv n benedisulfonate in the syntheses described in the fore- FOREIGN PATENTS going examples and substituting potassium chloride for 895,847 Fran e 17, 19

sodium chloride in the salting out operagion Where re- 596,324 Grea B it i M Jan 1, 1 g

uired. The free acids may be obtained y acidification 2f the sodium or potassium salts while other salts such H R REFERENCES as ammonium, hydroxyalkylamine salts and the like may Fieser and Fieser, Organic Chemistry, page 830 be obtained by the neutralization of the free acids. (1944). I

Where spirit soluble products are desired, i. e., in bright- Karrer, Organic Chemistry, page 468 (1946)..

ening of lacquers, etc., the higher alkyl or cycloalkyl- Whitmore, Organic Chemistry, pp. 661, 721 (1951). 

1. FLUORESCENT AGENTS SELECTED FROM THE GROUP CONSISTING OF COMPOUNDS OF THE FORMULA 